1. Field of the Invention
The present invention relates to an image processing method for selecting desirable images from among a plurality of images and to an apparatus thereof.
2. Description of the Related Art
In recent years, multi-functionalization of digital cameras are remarkable, in particular, digital cameras for a high speed continuous shooting have come into wide use. Such cameras perform a high speed continuous shooting within a predetermined time period, so that users won't miss defining shutter scenes. Further, recognition functions represented by face recognition and smile recognition and so forth have been also put to practical use, and have been widely adopted in the digital cameras. The recognition functions are capable of high speed processing, and development processing can be performed depending on the recognition processing and recognition results with respect to each image obtained by the high speed continuous shooting. Further, developed images are efficiently saved on a recording medium such as a flash memory by compressing the developed images in Joint Photographic Experts Group (JPEG) format or the like.
Further, as general functions of the digital cameras, captured images can be selected by a key operation or the like and displayed on a liquid crystal panel of a digital camera to confirm image qualities and desirability of the images. However, in the digital cameras provided with the high speed continuous shooting functions as described above, images to be captured amount to a very large number of frames, for instance, over several hundreds.
Therefore, a great many operations will be needed until reaching best-shots (desirable images) when a method for simply displaying captured images in a time-sequential manner is used like the conventional digital cameras. Furthermore, generally, there exist best-shots in a plurality of frames rather than in one frame out of a series of captured images. Hence, for the purpose of enhancing convenience of users, a function to automatically select such a plurality of frames of best-shots has been demanded.
Conventionally, for the purpose of an automatic selection of such best-shots, a method to utilize recognition scores recorded as additional information of images is employed. For instance, as an image selection technique using such recognition scores or the like, captured face images of photo-taken persons are extracted to make smile evaluation and propriety evaluation for each face image, and subsequently the images are displayed in a decreasing order of overall evaluation values (See, for instance, Japanese Patent Application Laid-Open No. 2004-46591). Further, in order to prevent similar images from becoming display targets when displaying a plurality of images, a degree of coincidence with newly read images for display is determined, and only images with a low degree of coincidence are displayed on a liquid crystal monitor (See, e.g., Japanese Patent Application Laid-Open No. 2006-217510).
FIG. 15 illustrates an example of desirability scores in a time-sequence used in a conventional best-shot selection method. In the conventional best-shot selection method, images are selected in a decreasing order of the desirability scores (recognition scores). In this method, as illustrated in FIG. 15, only images contained in an temporally close image group 1510 become selection targets. For a user, only one frame of best-shot chosen from an image group (image group having substantially the similar contents) that is taken at very close shooting times is enough. Thus, there is a need to find another best-shots from an image group (image group having different contents) taken at separate shooting times, even if the recognition score is somewhat low. However, in the conventional best-shot selection method as described above, there is a problem that many operations are required before reaching another best-shots which are different in contents, and have high recognition scores. On the other hand, in the conventional technique to simply display only images whose degrees of coincidence with already displayed images are low, even images with low recognition scores become the display targets, thus the display candidates become too many.